Jay,
   You are spot on.  I have actually seen E85 with percentages as low as 50%.  The "85" is just a maximum standard, no real minimum % standard exists as long as the fuel meets a few other performance requirements.

And yes, E85 loves boost.  I got to play around with it in a turbocharged 1100 cc twin cylinder snowmobile engine about a decade ago.  Spent many hours on the development dyno seeing what the engine could take and what the fuel system would support.  We stopped at 330 hp when the crank came out the bottom of the engine....  Ended up dialing it back to 280 hp and dropped it into a chassis.  It would about pull your arms out of your shoulders when the boost hit. 

I don't buy exhaust kits any more.  My stuff and what I work on is rarely stock, and therefore there is no sense since I will be cutting it up and modifying it to fit anyways.  I typically buy a bunch of stainless 180 deg. mandrel U or J bends and cut the bends I need and weld it back together.  Just finished a complete exhaust system for a '60 T-Bird.  FPA headers, and all stainless 3 inch tube after that.  The only "catalog" headers I have purchased in the past 10 years came from FPA.  I did purchase a 3.5" Banks kit for my '85 F350, still had to modify the down pipe coming off the turbo, but the rest fit pretty good.

If the bumpsides are anything like the '76 Dentside F250 (last of the 390's) I did a few years ago, it was very easy.  Mostly straight pipe and just a couple of bends.  Brought the drivers side over to the passenger side and ran both pipes parrallel down the passenger side.  Used a pair of "truck" can style mufflers and exited the pipes right behind the rear wheel.  It looked stockish, but definitely did not sound or preform like a stock system. 

Sounds like a Stage II Buick V6.  Snatch it up, find a mid 80's Camaro, drop it in and embarrass the heck out of all the 350 fanboys.  Stage II's have been known to make ridiculous (1500+ HP) power with the right turbo and 2+ HP/ci in NA form is also quite doable.

Can you use a standard resistor of say 35 or 40 ohms to bypass the sender and see if the gauge reacts appropriately?  Re-reading your original post definitely makes it sound like a ground issue, but using a known resistor may help point you in the right direction.

I wonder if the OP is ever going to come back???

I had this '76 F250 for quite a few years in the 2010's.  Factory 390 4bbl motor that the previous owner was kind enough to sell to me with a smoked head gasket.  Needless to say, the motor got a full rebuild. 

The recipe was fairly straight forward and budget minded:

Holley 600 cfm 4bbl
Howards' Dual pattern flat tappet cam
New flat tops for a 9:1 compression ratio
Long tube Headers
Stock Heads with a nice 3 angle valve job

Nothing exotic or expensive, and it would pull my 10,000 lb 24' Pace enclosed along at 65 mph all day, and roast the tires at a moments notice unloaded.  The biggest headache with the truck was the C6 and 4.11 rear gears.  I farted around with an AOD for a awhile, but could never get a tight enough stall on the small torque convertor dictated by the Quicktime bellhousing to run comfortably in OD without cooking the oil.  Hindsight being 20/20, I should have gone to a Gearvendors for the C6 or converted it to a manual OD.  Eventually sold it and the AOD setup, and replaced it with my '85 F350.

There is no reason you can't build your 360 to similar performance, just by following the basic hot rodding rules of getting air and fuel in and out more efficiently, and adding compression.  I.E. 4 bbl intake and carb, headers, new pistons to get in that 9 to 10:1 compression ratio range, performance cam, etc.

Fantastic Work Kelly!

Not to steal your thunder, but the MEL Blower Intake is getting closer to becoming real as well.

This would be a good "guess" - the bearing is the "victim" of something else in the system.  Could be damn near anything.  Given the level of electronic management in a new engine package, it could even be something in the software that controls timing and fuel.  A bearing (or rod etc.) design that just meets or barely exceeds design needs won't have enough "headroom" to handle any unexpected loads.

Your right, the bearing is normally the weak link that results in engine failure, rarely the actual problem or root cause.  I have seen something similar on 3.9 Cummins 4BT Industrial motors.  Ran fine and forever at the factory rated 85 Hp, but as soon as farmers started fiddling with the fuel pumps and attempting to squeeze a bit more power out of them, the rod bearings would quickly fail.  Granted these were cheap aftermarket bearings, not Cummins OE, but the difference in lifespan between a stock 85 hp motor and one that had been turned up was startling. 

According to the  Chev dealer local, the problem is crankshaft surface finish. I am surmising that going to a heavier oil, just delays the inevitable failure.

If the root cause is incorrect surface finish, changing oil viscosity will do very little to help, and it might actually make it worse as the thicker oil just causes the Oil Pressure Relief Valve to open further and you see a larger pressure drop from one end of the crank to the other.  In other words, the bearings furthest from the pump may be getting starved, especially at startup and low operating temps when the oil is at it's thickest.

No Doubt!!!  I have been working with a CAT dealer that has been having problems with its rental fleet of large air compressors (540 HP 15L C15 engines in each compressor).  They have been changing oil at the bare minimum interval of 500 hrs (and sometimes after more hours than that), but there have been a large number of front and rear main seal leaks and turbo bearing failures.  CAT Engineering recommends changes more frequently if used in "extreme" environments, and these units are often placed in shipyards to support sandblasting operations, so salt air and silica dust definitely qualify for an extreme use environment.  Add in the units being equipped with the "smaller" 38 Quart truck pan vs the 76 Quart industrial pan and this all adds up to engines going down on a frequent basis, which is very expensive for the rental fleet manager.  Convincing them to up the maintenance frequency has been a challenge, despite the fact that a rebuild for one these engines can cost up to $50K.